i have coredata and i want to add bool Optional but i get error: import CoreData @objc(HistoryData) class HistoryData: NSManagedObject {       @NSManaged var firstName: String   @NSManaged var lastName: String   @NSManaged var telephone: String   @NSManaged var time: String   @NSManaged var callHidden: Bool? // Here the error } Error: Property cannot be marked @NSManaged because its type cannot be represented in Objective-C in xcdatamodeld it selected Optional but it not do it.. why?

How i can open Location services direct to my app? I want it to go to the screen where the user chooses allow location or not can be enabled in the app.. UIApplication.shared.open(URL(string: "App-prefs:LOCATION_SERVICES")!) this code open for me only the location services but how i can open location setting to my app?

I have the code: if let url = URL(string:"tel://\(String(describing: Util.checkForNullString(contactNo)))"), UIApplication.shared.canOpenURL(url){ if #available(iOS 10, *) { UIApplication.shared.open(url) } else { UIApplication.shared.openURL(url) } } how I can detected if user calling or dismiss?

how i make a List like at swiftui at storyboard? the UITableView not the same.. look image: https://i.ibb.co/Qn69TRR/Untitled.png how i can do List like a swiftui in storyboard?

i maked core data and i fetch all data to List. all working (add ,delete) but! if the app inactive (to background) and i open again to delete a row it crashes with error: "Thread 1: "An NSManagedObjectContext cannot delete objects in other contexts." struct HistoryView: View {   @State private var history: [HistoryList] = [HistoryList]()   let coreDM: CoreDataManager       var dateFormatter: DateFormatter {     let formatter = DateFormatter()     formatter.dateFormat = "MM-dd-yyyy HH:mm"     return formatter   }       private func populateHistory(){     history = coreDM.getAllHistory()   }       var body: some View {     NavigationView{       VStack {         if !history.isEmpty {           List {             ForEach(history, id: \.self) { historyList in               HStack {                 Text(dateFormatter.string(from: historyList.dateFlash ?? Date(timeIntervalSinceReferenceDate: 0)))                 Text("\(historyList.timerFlash)s")                   .multilineTextAlignment(.trailing)                   .frame(maxWidth: .infinity, alignment: .trailing)               }             }.onDelete(perform: { indexset in               indexset.forEach { index in                 let history = history[index]                 coreDM.deleteHistory(history: history)                 populateHistory()               }             })           }.refreshable {             populateHistory()             print("## Refresh History List")           }         } else {           Text("History Flashlight is Empty")         }       }       .onAppear {         populateHistory()         print("OnAppear")       }     }.navigationTitle("History Flashlight")       .navigationBarTitleDisplayMode(.inline)   } } struct HistoryView_Previews: PreviewProvider {   static var previews: some View {     HistoryView(coreDM: CoreDataManager())   } } why?

why the setTorchModeOn not working? it not change the level torch     guard let device = AVCaptureDevice.default(for: .video) else { return }     if device.hasTorch {       do {         try device.lockForConfiguration()         try device.setTorchModeOn(level: 0.1)         if on == true {           device.torchMode = .on         } else {           device.torchMode = .off         }         device.unlockForConfiguration()       } catch {         print("Torch could not be used")       }     } else {       print("Torch is not available")     }   }

i have NavigationView in my code i do this for button it Navigation       Button{         print("")       }label: {         Image(systemName: "list.dash")           .foregroundColor(.gray)       }     } how i can navigate to another view when user click the button??

i created a list with colors and i want when the user click red so all the screen was background red, if user click green so full background is green... i don't know why but the var not change..   var body: some View {           NavigationView {       List {         Section {           ScreenColorButtons(text: "Red", color: .red)           ScreenColorButtons(text: "Green", color: .green)           ScreenColorButtons(text: "Blue", color: .blue)         }       }     }   } } struct ScreenColorButtons: View {       @State static var screenSelected: Color = Color.red       var text: String   var color: Color       var body: some View{     Button(action: {       ScreenColorButtons.screenSelected = color       print(ScreenColorButtons.screenSelected)     }, label: {       NavigationLink(text){}     })   } } the ScreenColorView: struct ScreenColorView: View {   @Environment(\.presentationMode) var presentationMode       var body: some View {     Color.ScreenColorButtons.screenSelected   } } why the var not change and error to background??? thank for answer

why when i Swipe the table view the swipe not disappear? see screenshot It just gets stuck like that and won't come back, why?  func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {     let item = realArray[indexPath.row]     let callAction = UIContextualAction(style: .normal, title: "Call Private", handler: { (action, view, success) in       self.service.dialNumber(number: item.telephone, prefixNumber: true)       self.service.setupCallerId(firstName: item.firstName, lastName: item.lastName, telephone: item.telephone)     })     callAction.backgroundColor = .systemGreen     let configuration = UISwipeActionsConfiguration(actions: [callAction])     return configuration   }

i have this code: https://stackoverflow.com/a/50999497/19364094 and when i try to call func showCallAlert() from another ViewController it it not working for me and it not detect if user click call or cancel what it can do?

how i can convert my xcode project to ipa? i read all the methods but it very old (all methods for xcode 9) and not working.. what i can do?

I know there is a problem with this. But I still ask if this is possible to develop call recording in swift?

I made an extension to UIViewController and inside i have function I use several times: extension UIViewController {   func transitionToHomeVC() {     let homeViewController = self.storyboard?.instantiateViewController(withIdentifier: NameConstants.StoryBoard.homeViewController) as? HomeViewController     self.view.window?.rootViewController = homeViewController     self.view.window?.makeKeyAndVisible()   } } And I have a registration button and as soon as you click if the information was received and correct and etc ... then he has to move me at the to the HomeViewController screen and he does not do it. He does all the actions but does not pass to screen. @IBAction func signUpTapped(_ sender: Any) {     // Validate the fields     let error = validDataFields()     if error != nil {       // There's something wrong with the fields, show error message       Service.showError(vc: self, message: error!)     }     else {       // Create cleaned versions of the data       let fireName = firstNameTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)       let lastName = lastNameTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)       let email = emailTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)       let password = passwordTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)            // Create the user       Auth.auth().createUser(withEmail: email, password: password) { resulte, err in         // Check for errors         if err != nil {           // There was an error creating the user           Service.showError(vc: self, message: "Error creating user \n make sure you enter: \n current email")         }         else {           // User was created successfully, now store the first name and last name           let db = Firestore.firestore()           db.collection("users").addDocument(data: ["firstName":fireName,"lastName":lastName, "uid": resulte!.user.uid]) { error in             if error != nil {               // Show error message               Service.showError(vc: self, message: " Error saving user Data")             }           }           self.transitionToHomeVC()         }       }     }   }     why it not move to homeViewController?

class Service: UIViewController {       static func showError(_ message:String) {     // Create new Alert     let dialogMessage = UIAlertController(title: "Error", message: message, preferredStyle: .alert)           // Create OK button with action handler     let ok = UIAlertAction(title: "OK", style: .default, handler: { (action) -> Void in       print("Ok button tapped")     })           //Add OK button to a dialog message     dialogMessage.addAction(ok)     // Present Alert to     self.present(dialogMessage , animated: true, completion: nil)         } } why i get error in this line: self.present(dialogMessage , animated: true, completion: nil) the error: Instance member 'present' cannot be used on type 'Service' why?